Improvement in tension-indicators for sewing-machines



' izin the tension in sewing-machines as will as shown. To theV spring Gis attached a| UNITED STATEs PATENT OFFICE.

DAvID B. TIFFANY, oF XENIA, oHIo.

IMPROVEMENT IN TENSION-INDICATORS FOR SEWING-MACHlNES. f

Specification forming part of Letters Patent No. 136,626, dated March1l, 1873.

To all whom t'may concern:

Beit known that I, DAVID B. TIFFANY, of Xenia, in the county of Greeneand State of Ohio, have invented certain new and useful Improvements inTension-Indicators for Sewing-Machines; and I do hereby declare that'the following is a full, clear, and exact description thereof',reference being had to the accompanying drawing and to the letters ofreference marked thereon which form a part of this specication.

My invention consists in a device for equalbe hereinafter more fully setforth.

In order to enable others skilled in the art to which my inventionappertains to make and use the same, I will now proceed to describe itsconstruction and operation, referring to the annexed drawing whichrepresents a perspective View ot' my invention.

A represents the frame of my device, consisting of a metal .bar bent asshown to form the 'curved portionva., and the ends of the bar united toform the/handle B. One side of the frame A, from the end of the curvedpart a to the handle B, is nearly straight, while the other side is morebent or curved. Between the ends of the bar forming the frame A, wherethe same are united to form the handle B, is secured a sp1-in g, C,which extends up along the nearly straight part of the frame and passesthrough a slot, b, in the curved part a of the frame. The upper end ofthe spring O is provided with one or more notches or slots,

spring pawl, D, to engage with teeth i' i formed on the upper surface ofthe curved part a of the fra-me.

The operation of this device is as follows: The end of theshuttle-thread is putin the slot or slots of the spring C, so as not toslip; then pull back until the spring will not give any more, but on thecontrary move the shuttlebobbin. The pawl D, sliding over and catchingin the teeth 'i i', holds the spring C at this point, which indicatesthe resistance. Then take out the thread and go through the sameoperation with the upper tension, adjusting said upper tension until thespring will indicate the same resistance. These operations equalize bothtensions, both showing the same amount ot' resistance, which is verydesirable in doing good and neat sewing.

On one edge or both edges of the curved part a are indicating-marks toset or adjust the tension for fine or coarse sewing.

Having thus fully described my invention,

what I claim as new, and desire to secure by Letters Patent, is-

The combination of the frame A, construct ed as described, with slot band teeth c' fi, the spring C andpawl D, all substantially as and forthe purpose herein set forth.

In testimony that I claim the foregoing as my own, I atiix my signaturein presence 0f two witnesses.

DAVID B. TIFFANY. Witnesses:

F. C. FREBEIN, J. R. RIDENOUR.

